The task of delivering items from a conveyor system to e.g. a package tray under the requirement that the items are placed neatly, e.g. in a shingle fashion, is often particularly challenging for relatively flat and floppy items such as e.g. sliced or filleted items of meat, poultry or fish, e.g. beefsteaks, pork chops, turkey breast steaks, etc.
Typically the task is performed by delivering the items on a conveyor with a variable end point. By retracting the end point concurrently with the items being delivered to a tray placed immediately below the conveyor, the items will be placed neatly in a shingle fashion in the tray. This conventional method is, however, relatively slow, and it may be useless if the items are not placed correctly on the conveyor at the correct intervals, or e.g. when the items are already placed in a neat, shingle fashion on the conveyor, i.e. completely or partly batched on the conveyor.
As an alternative to the above, a concept has been developed of dropping machines where the items or complete batches are dropped into the package trays by removing their support when positioned directly above the tray.
For example in U.S. Pat. No. 3,848,725, an apparatus for handling meat articles is disclosed, where the articles are delivered to a kind of trap door established by two horizontal banks of rollers arranged in parallel in such a way that the meat articles delivered thereto are supported partly by both rollers. When the meat articles are positioned above the desired position, the roller banks are pivoted 90 degrees downwards around axes corresponding to the outer edges of the roller banks parallel to the transport direction, i.e. in a trap door fashion. The meat articles being equally supported by both roller banks thus loose their support and drops down to the desired position, e.g. a weighing device, a conveyor, a packager, etc. A problem with the trap door approach is, however, that the meat articles may not always drop vertically and neatly, in particular not if the doors do not open exactly uniformly, if the meat articles are not supported exactly equally by both roller banks, or if the meat articles do not stick equally to both roller banks.
For example in European patent application No. 0 359 339 A1, an apparatus for shaping objects such as filled bags and delivering them into boxes is disclosed. The shaping, transportation and positioning is performed by a pair of converging, vertical guide belts, which take a filled bag along on a pair of pivotable flaps, i.e. a trap door arrangement, until it is positioned over an appropriate box. The positioning includes both lateral and longitudinal positioning. The flaps pivot downwardly to vertically drop the bag into the box, while the bag still engages the guide belts to maintain its position. A problem with this apparatus is that it is only able to handle relatively high, squeezable objects, such as filled bags. It would not be possible to position e.g. flat, floppy, sticky pieces of meat by means of vertical guide belts, and the guide belts would neither be able to keep the meat at the correct position upon opening of the trap door.
For example in European patent application No. 0 605 740 A1, an apparatus for transferring bags of items from a conveyor to a box is disclosed. In one embodiment the bags are delivered to a pair of conveyors arranged in parallel in a trap door arrangement. When the bags are at the desired position, a suction unit is lowered into contact with the bags and suction is engaged to keep the bags in place when the conveyor trap door opens. The suction unit holding the bags is further lowered through the trap door opening and into a box positioned beneath. When the bags reach the bottom of the box, the suction is disengaged, the suction unit is raised to its initial position, and the trap door is closed, ready for the next plurality of bags. In another embodiment, it is disclosed that the two parallel conveyors are pulled away from each other horizontally, thereby forming an opening beneath the bags. This embodiment also engages the suction unit to hold the bags and lower them in a controlled way through the opening into a box beneath. Even though both of these embodiments engage the suction unit to ensure that the bags are arranged in the box in the same way as they were on the conveyor, the suction unit also constitutes a major disadvantage in terms of time and complexity. Moreover, even though suction techniques may be readily applicable for handling of plastic bags, the complexity and requirements of the suction unit increase significantly when the task involves handling and neat positioning of items such as flat, floppy pieces of meat.
An object of the invention is to provide an apparatus that can deliver items, including complete or partial batches of items, quickly but also neatly into e.g. trays in a simple fashion.